In a sweeping, 138-page report, the Justice Department’s Office of Inspector General cited “serious deficiencies” in the work of the task force assigned in 1996 to follow up on potentially troublesome crime lab cases. In some instances, the problems associated with 13 specific lab workers were a matter of life and death.

“We found that it took the FBI almost 5 years to identify the 64 defendants on death row whose cases involved analyses or testimony by 1 or more of the 13 examiners,” investigators noted. “The department did not notify state authorities that convictions of capital defendants could be affected by involvement of any of the 13 criticized examiners.”

The investigators cited the case of death row inmate Benjamin H. Boyle, executed in Texas in 1997 before the task force had a chance to review the crime lab’s role in his conviction.

“The prosecutor deemed the Lab analysis and testimony in that case material to the defendant’s conviction,” the new investigation noted. “An independent scientist who later reviewed the case found the FBI Lab analysis to be scientifically unsupportable and the testimony overstated and incorrect.”

As previously reported, three other defendants, Donald E. Gates, Santae A. Tribble, and Kirk L. Odom, had served sentences in excess of 21 years based in part on FBI hair analyses and testimony that DNA analysis subsequently proved erroneous.

The report made public Wednesday was the third since 1997 to follow up on irregularities at the famed FBI lab. The prior inspector general reports focused on lab problems. The new report focused on the Justice Department’s task force created to identify and follow up on the cases involving scientifically unsupportable analysis and overstated testimony by FBI Lab examiners.

The task force identified about 8,000 state and federal cases involving work by the 13 criticized examiners, of which about 2,900 resulted in convictions. In its official reponse to the OIG report, the Justice Department notes that in the “vast majority” of these cases, prosecutors concluded that the lab’s work was “not material” to the convictions.

The new report said the Justice Department “failed to ensure that prosecutors made appropriate and timely disclosures to affected defendants” and that the department “failed to staff the Task Force with sufficient personnel to implement a case review of the magnitude it undertook.” The work took far too long, investigators said.

At the same time, investigators acknowledged that “almost all of the problems we identified with the Department’s and the FBI’s design and management of the FBI Lab case review occurred long ago and most of the employees responsible for the review have left the Department or the FBI.”

In its formal response, the Justice Department said that while “a number of the OIG’s criticisms are valid,” others are “unsupported.”

“Decades ago, the FBI corrected the deficiencies that led to the creation of the Task Force,” the department noted in its official response, adding that the Task Force’s work was “unprecedented both in its magnitude and its complexity.”